Multi-tip steerable catheter

ABSTRACT

An improved catheter is provided that is particularly useful for simultaneously mapping electrical activity at multiple locations within the heart. The catheter comprises an elongated catheter body having proximal and distal ends and at least one lumen extending longitudinally therethrough. A control handle is attached to the proximal end of the catheter body. A mapping assembly is mounted to the distal end of the catheter body. The mapping assembly comprises at least two elongated flexible spines, each spine having a proximal end attached to the distal end of the catheter body and a free distal end. Each spine carries at least one electrode along its length. The catheter further comprises at least two spine puller wires, each spine puller wire corresponding to one of the at least two spines. Each spine puller wire has a proximal end anchored in the handle and a distal end anchored at or near the distal end of its corresponding spine such that, in use, longitudinal movement of a spine puller wire relative to the catheter body results in deflection of the spine in which the spine puller wire is anchored. The use of a plurality of spines permits simultaneous mapping of multiple points, increasing the speed of mapping of regions of interest.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. ProvisionalApplication No. 60/422,227, filed Oct. 30, 2002, the entire disclosureof which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] Electrophysiology catheters are commonly used for mappingelectrical activity in a heart. By mapping the electrical activity inthe heart, one can detect ectopic sites of electrical activation orother electrical activation pathways that contribute to heartmalfunctions. This type of information may then allow a cardiologist tointervene and destroy the malfunctioning heart tissues. Such destructionof heart tissue is referred to as ablation, which is a rapidly growingfield within electrophysiology and obviates the need for maximallyinvasive open heart surgery.

[0003] Such electrophysiology mapping catheters typically have anelongated flexible body with a distal end that carries one or moreelectrodes that are used to map or collect electrical information aboutthe electrical activity in the heart. The distal end can be steerable ordeflectable to assist the user in properly positioning the catheter formapping in a desired location. However, often numerous electricalmeasurements must be taken to properly map the heart, which can be timeconsuming if the measurements are taken one at a time. Accordingly, aneed exists for an improved catheter that can take multiple measurementssimultaneously to make the mapping process more efficient.

SUMMARY OF THE INVENTION

[0004] The present invention is directed to an improved catheter formapping the electrical activity in a heart. The catheter comprises aplurality of deflectable spines, each capable of obtaining electrical,mechanical and/or locational data. The use of a plurality of spinespermits simultaneous mapping of multiple points, increasing the speed ofmapping of regions of interest, e.g., the left and right ventricles.

[0005] In one embodiment, the invention is directed to a cathetercomprising an elongated catheter body having a proximal end, a distalend and at least one lumen extending longitudinally therethrough. Acontrol handle is attached to the proximal end of the catheter body. Amapping assembly is mounted at the distal end of the catheter body. Themapping assembly comprises at least two elongated flexible spines, eachspine having a proximal end fixedly attached at or near the distal endof the catheter body and a free distal end. Each spine carries at leastone electrode along its length. The catheter further comprises at leasttwo spine puller wires, each spine puller wire corresponding to one ofthe at least two spines. Each spine puller wire has a proximal endanchored in the handle and a distal end anchored at or near the distalend of its corresponding spine such that, in use, longitudinal movementof a spine puller wire relative to the catheter body results indeflection of the spine in which the spine puller wire is anchored.

DESCRIPTION OF THE DRAWINGS

[0006] These and other features and advantages of the present inventionwill be better understood by reference to the following detaileddescription when considered in conjunction with the accompanyingdrawings wherein:

[0007]FIG. 1 is a perspective view of a catheter according to theinvention.

[0008]FIG. 2 is an end cross-sectional view of the catheter body of FIG.1 taken along line 2-2.

[0009]FIG. 3 is an end cross-sectional view of a spine of the catheterof FIG. 1 taken along line 3-3.

[0010]FIG. 4 is a side cross-sectional view of the control handle of thecatheter of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

[0011] The invention is directed to a catheter having at its distal enda mapping assembly comprising a plurality of steerable or deflectablespines. Each spine carries one or more electrodes such that, when thespines are positioned in contact with heart tissue, each spine iscapable of obtaining electrical data.

[0012] As shown in FIG. 1, the catheter comprises an elongated catheterbody 12 having proximal and distal ends, a mapping assembly 13comprising a plurality of spines 14 mounted at the distal end of thecatheter body, and a control handle 16 at the proximal end of thecatheter body.

[0013] As shown in FIGS. 1 and 2, the catheter body 12 comprises anelongated tubular construction having a single, axial or central lumen15, but can optionally have multiple lumens along all or part of itslength if desired. The catheter body 12 is flexible, i.e., bendable, butsubstantially non-compressible along its length. The catheter body 12can be of any suitable construction and made of any suitable material. Apresently preferred construction of the catheter body 12 comprises anouter wall 18 made of polyurethane or PEBAX® (polyether block amide).The outer wall 18 preferably comprises an imbedded braided mesh ofstainless steel or the like, as is generally known in the art, toincrease torsional stiffness of the catheter body 12 so that, when thecontrol handle 16 is rotated, the distal end of the catheter body 12will rotate in a corresponding manner.

[0014] A stiffening sleeve 19 is coaxially mounted in the lumen 15 ofthe catheter body 12 to provide improved torsional stability. Thestiffening sleeve 19 preferably has an outer diameter that is slightlysmaller than the inner diameter of the outer wall 18. The stiffeningsleeve 19 is preferably made of polyimide or other suitablebiocompatible plastic. If desired, the stiffening sleeve can beeliminated.

[0015] The length of the catheter body 12 is not critical, butpreferably ranges from about 90 cm to about 120 cm, and more preferablyis about 110 cm. The outer diameter of the catheter body 12 is also notcritical, but is preferably no more than about 8 french, more preferablyabout 7 french. Likewise, the thickness of the outer wall 18 is notcritical, but is preferably thin enough so that the central lumen 15 canaccommodate all necessary wires and other components extending throughthe catheter body 12.

[0016] In the depicted embodiment, the mapping assembly 13 comprisesthree spines 14. As will become apparent, the number of spines can varyas desired, and preferably ranges from two to twelve, more preferablyfrom three to eight. Each spine 14 has a proximal end attached at thedistal end of the catheter body 12 and a free distal end, i.e., thedistal end is not attached to any of the other spines, to the catheterbody, or to any other external structure that confines movement of thedistal end. Each spine 14 comprises a plastic tubing made of anysuitable biocompatible material, such as PEBAX or polyurethane, havingone or more lumens extending therethrough. Preferably each spine 14comprises a multi-lumen, more preferably a dual-lumen, extrusion. In thedepicted embodiment, each spine includes a lead wire lumen 26 and apuller wire lumen 27, discussed further below. The puller wire lumen 27is preferably off-axis. As would be recognized by one skilled in theart, the number, sizes and arrangement of the lumens can vary asdesired. The lengths the spines will depend on the particularapplication for which the catheter is being used. Preferably each spinehas a length ranging from about 0.5 cm to about 25 cm, more preferablyfrom about 1 cm to about 10 cm, still more preferably from about 2 cm toabout 7 cm.

[0017] If desired, each spine 14 can have a preformed shape. This can beaccomplished by including in each spine 14 a support arm (notshown)comprising a metal or plastic material that has shape memory, suchas nitinol, so that the support arm forms an initial shape when noexternal forces are applied, forms a deflected shape when an externalforce is applied, and returns to its initial shape when the externalforce is released. Such a design is disclosed in U.S. patent applicationSer. No. 10/231,875, entitled “Catheter and Method for Mapping PurkinjeFibers,” the entire disclosure of which is incorporated herein byreference.

[0018] The spines 14 are connected to each other and to the distal endof the catheter body 12 at their proximal ends, as shown in FIG. 1.Preferably the proximal ends of the spines 14 are melted, glued orotherwise fused to each other and to the distal end of the catheter body12 at a junction 24 to provided a unitary construction. Thus the spines14 are permanently attached to the catheter body 12 and not retractableinto the catheter body.

[0019] In the depicted embodiment, the distal end of each spine 14 hasan atraumatic tip comprising a polyurethane cap 22. Each polyurethanecap is glued or otherwise fixedly attached to the distal end of itscorresponding spine 14. Other atraumatic tip designs could be used inconnection with the invention.

[0020] As described in more detail below, the spines 14 are moveablebetween a deflected arrangement, wherein, for example, each spineextends outwardly from the catheter body 12, or the spines 14 may bearranged in a collapsed arrangement, wherein, for example, each spine isdisposed generally parallel to the longitudinal axis of the catheterbody 12 so that the spines are capable of fitting within a lumen of aguiding sheath, as discussed further below.

[0021] Each spine 14 carries at least one electrode mounted along itslength. In the depicted embodiment, five ring electrodes 28 are mounted,preferably evenly-spaced, on each spine 14. As would be recognized byone skilled in the art, the number and arrangement of the electrodes oneach spine can vary as desired. For example, one or more of the spines14 could carry a tip electrode (not shown) on the distal end of thespine in place of the polyurethane cap 22. Each ring electrode 28 has alength preferably up to about 2 mm, more preferably from about 0.5 mm toabout 1 mm. The distance between the ring electrodes 28 preferablyranges from about 1 mm to about 10 mm, more preferably from about 2 mmto about 5 mm. Preferably each spine carries from 2 to about 20electrodes, more preferably from 3 to 10 electrode.

[0022] Each ring electrode 28 is electrically connected to an electrodelead wire 29, which in turn is electrically connected to a connector 17at the proximal end of the catheter. The connector 17 is connected to anappropriate mapping or monitoring system (not shown). Each electrodelead wire 29 extends from the connector 17, through the control handle16, through the central lumen 15 in the catheter body 12, and into thelead wire lumen 26 of the spine 14 where it is attached to itscorresponding ring electrode 28. Each lead wire 29, which includes anon-conductive coating over almost all of its length, is attached to itscorresponding ring electrode 28 by any suitable method.

[0023] A preferred method for attaching a lead wire 29 to a ringelectrode 28 involves first making a small hole through the wall of thespine 14. Such a hole can be created, for example, by inserting a needlethrough the wall of the spine 14 and heating the needle sufficiently toform a permanent hole. The lead wire 29 is then drawn through the holeby using a microhook or the like. The end of the lead wire 29 is thenstripped of any coating and welded to the underside of the ringelectrode 28, which is then slid into position over the hole and fixedin place with polyurethane glue or the like. Alternatively, each ringelectrode 28 may be formed by wrapping the lead wire 29 around the spine14 a number of times and stripping the lead wire of its ownnon-conductive coating on its outwardly facing surfaces. In such aninstance, the lead wire 29 functions as a ring electrode.

[0024] Additionally, a mechanism is provided for individually deflectingor steering each of the spines 14. Specifically, a spine puller wire 32is provided for each spine 14. Each spine puller wire 32 has a proximalend anchored to the control handle 16, as described further below, and adistal end anchored at or near the distal end of its corresponding spine14. Each spine puller wire 32 extends through the puller wire lumen 27of its corresponding spine and through the central lumen 15 of thecatheter body 12. Each spine puller wire 32 is made of any suitablemetal, such as stainless steel or Nitinol, and is preferably coated withTeflon® or the like to impart lubricity to the puller wire. Each pullerwire 32 preferably has a diameter ranging from about 0.006 to about0.010 inches. Within each spine 14, a plastic, preferably Teflon®,protective sleeve 33 is provided in surrounding relation to each pullerwire 32 to prevent the puller wire from cutting through the wall of thespine during deflection.

[0025] A preferred mechanism for anchoring a spine puller wire 32 to itscorresponding spine 14 comprises a T-bar anchor, as generally describedin U.S. Pat. Nos. 5,893,885 and 6,066,125, the entire disclosures ofwhich are incorporated herein by reference. If a spine 14 carries a tipelectrode, the spine puller wire 32 can be anchored in the tipelectrode, as also described in U.S. Pat. No. 6,066,125. Alternatively,a spine puller wire 32 can be attached to the side of the spine 14, asgenerally described in U.S. Pat. No. 6,123,699, the entire disclosure ofwhich is incorporated herein by reference. Other arrangements foranchoring a spine puller wire to the distal end of a spine are includedwithin the scope of the invention.

[0026] A compression coil 34 is situated within the catheter body 12 insurrounding relation to each spine puller wire 32. Each compression coil34 extends from the proximal end of the catheter body 12 to the junction24 of the catheter body and mapping assembly 13. Each compression coil34 is made of any suitable metal, preferably stainless steel. Eachcompression coil 34 is tightly wound on itself to provide flexibility,i.e., bending, but to resist compression. The inner diameter of eachcompression coil 34 is preferably slightly larger than the diameter ofits corresponding spine puller wire 32. The Teflon® coatings on thepuller wires 32 allows them to slide freely within the compression coils34. If desired, the outer surface of each compression coil 34 can becovered by a flexible, non-conductive sheath (not shown), e.g., made ofpolyimide tubing, to prevent contact between the compression coil 34 andthe lead wires 29 within the catheter body 12.

[0027] A catheter puller wire 36 can also be provided for deflection ofthe distal end of the catheter body 12 near the junction 24 of thecatheter body and mapping assembly 13. With such a design, the catheterpuller wire 36 is anchored at its distal end to the outer wall 13 of thecatheter body near the junction 24, as generally described in U.S. Pat.No. 6,123,699, and is anchored at its proximal end to the control handle16, as discussed further below. Within the catheter body 12, thecatheter puller wire 36, like the spine puller wires 32, extends througha compression coil 34. If desired, the distal end of the catheter body12 can comprise a piece of tubing (not shown) that is more flexible thanthe rest of the catheter body and that contains an off-axis lumen (notshown) into which the distal end of the catheter puller wire 36 extends,as generally described in U.S. Pat. No. 6,123,699.

[0028] Longitudinal movement of a spine puller wire 32 relative to thecatheter body 12, which results in deflection of the corresponding spine14, is accomplished by suitable manipulation of the control handle 16.Similarly, longitudinal movement of the catheter puller wire 36 relativeto the catheter body 12, which results in deflection of the distal endof the catheter body proximal to the mapping assembly 13, isaccomplished by suitable manipulation of the control handle.

[0029] As shown in FIGS. 1 and 4, a preferred control handle comprises agenerally cylindrical housing 40 having a piston chamber 42 at itsdistal end. A generally cylindrical piston 44 is disposed within andgenerally coaxial with the piston chamber 42. The piston 44 includes acircumferential O-ring notch 46 that carries an O-ring 48 to provide asnug, watertight fit between the piston and the wall of the pistonchamber 42. The piston 44 has an axial bore 50 along its length. Thediameter of the axial bore 50 is approximately the same as the outerdiameter of the catheter body 12. The proximal end of the catheter body12 extends into the axial bore 50 and is fixedly attached, for example,by glue, to the piston 44. The spine puller wires 32, catheter pullerwire 36, and electrode lead wires 29 extend from the catheter body 12,through the axial bore 50 of the piston 44 and into the control handle16.

[0030] The distal end of the piston 44 extends beyond the distal end ofthe housing 40 so that it can be manually controlled by the user. Anannular thumb control 52 is attached at or near the distal end of thepiston 44 to facilitate lengthwise movement of the piston relative tothe housing 40.

[0031] The proximal end of the catheter puller wire 36 is anchored tothe housing 40 by any suitable method. In the depicted embodiment, thecatheter puller wire 36 is anchored to the housing by means of an anchor54 that extends into a transverse hole in the housing proximal to thepiston chamber 42. Such a design is described in more detail in U.S.Pat. No. 5,383,923, the entire disclosure of which is incorporatedherein by reference. In use, the distal end of the catheter body 12 canbe curved or bent by moving the piston 44 distally out of the pistonchamber 42 by pushing outwardly on the thumb control 52.

[0032] For longitudinal movement of the spine puller wires 32, thehousing includes three longitudinal slots 56, preferably generallyevenly-spaced about its circumference. A slider 58 is slidably mountedin each longitudinal slot 56, as best shown in FIG. 1. The proximal endof each spine puller wire 32 is anchored to the portion of itscorresponding slider 58 that is contained within the handle housing 40by any suitable method. A suitable method for anchoring a spine pullerwire 32 to a slider 58 involves a short stainless steel tubing 60 or thelike mounted on the proximal end of the puller wire. The slider 58includes an opening 62 for receiving the stainless steel tubing 60 and achannel 64 distal to the opening having a size that permits a spinepuller wire 32 to pass therethrough but that prevents the stainlesssteel tubing from passing therethrough. Other mechanisms for anchoringthe spine puller wires 32 to the sliders 58 are within the scope of theinvention.

[0033] Other control handles capable of manipulating a plurality ofpuller wires can also be used in connection with the invention. Examplesof such handles are disclosed in U.S. Pat. No. 6,066,125 and U.S. patentapplication Ser. No. 09/710,210, entitled “Deflectable Catheter withModifiable Handle,” the disclosures of which are incorporated herein byreference.

[0034] If desired, each spine 14 can also include one or more locationsensors (not shown), such as an electromagnetic location sensor, forconveying locational information about the electrodes on the spine. Useand design of such location sensors are described in more detail in U.S.application Ser. No. 10/040,932, entitled “Catheter Having MultipleSpines Each Having Electrical Mapping and Location SensingCapabilities,” the disclosure of which is incorporated herein byreference.

[0035] To use the catheter of the invention, a cardiologist orelectrophysiologist introduces a guiding sheath and a dilator into thepatient, as is generally known in the art, so that the distal ends ofthe sheath and dilator are in the region of the heart to be mapped. Thedilator is removed from the guiding sheath, and the catheter isintroduced into the patient through the guiding sheath. To insert thecatheter into the guiding sheath, the mapping assembly 13 must be in itscollapsed arrangement, wherein each spine 14 is disposed generally alongthe longitudinal axis of the catheter body 12. A suitable guiding sheathfor use in connection with the catheter is the PREFACE™ Braided GuidingSheath (commercially available from Biosense Webster, Inc., Diamond Bar,Calif.). Such a guiding sheath has sufficient strength to hold eachspine 124 in the collapsed arrangement, such that the spines and alsothe entire remainder of the catheter can travel within the guidingsheath, from an insertion point in the patient, through a vein or arteryand to a desired location in the heart.

[0036] Once the distal end of the catheter has reached the desiredlocation, such as a position within the left ventricle of the heart,relative longitudinal movement between the catheter and the guidingsheath is provided to allow at least a portion, and preferably all, ofeach spine 14 to protrude from the guiding sheath. Preferably theguiding sheath is moved proximally relative to the distal end of thecatheter to expose the spines 14. When a spine 14 protrudes from theguiding sheath, the user can then use control handle to manipulate thecorresponding spine puller wire 32 to deflect that spine so that it canbe positioned in a desired region for mapping. Preferably at least oneelectrode from each spine 14 is placed into contact with a firstplurality of the heart tissue such that electrical, and optionallylocational and mechanical, information can be obtained from thecontacted heart tissue. The spines 14 can then be further deflected orundeflected and/or repositioned to a second arrangement to contact asecond plurality of heart tissue such that electrical, and optionallylocational and mechanical, information can be obtained from thesetissues as well.

[0037] After mapping is completed, the catheter is moved proximallyrelative to the guiding sheath to retract the spines within the sheath.During mapping, the region between the spines 14 can be prone tothrombus formation, which can make it difficult to withdraw the spinesback into the sheath. To minimize such thrombus formation, irrigationfluid may be introduced through the catheter using an irrigation tube(not shown), as generally described in U.S. patent application Ser. No.10/040,932, entitled “Catheter Having Multiple Spines Each HavingElectrical Mapping and Location Sensing Capabilities.”

[0038] Using the inventive catheter having multiple spines, each havingelectrical and optionally mechanical mapping and locational sensingcapabilities, the cardiologist can map local activation time and obtainvoltage maps. The cardiologist can also determine those locations in theheart having no mechanical activity by monitoring whether the positionof the location sensor changes over a complete cardiac cycle. Thisinformation can guide the cardiologist in providing therapy to thepatient. For example, where the cardiologist finds regions of the heartthat do not have mechanical activity, he or she can revascularize thoseregions using known techniques, such as gene therapy or transmyocardialrevasularization. The inventive catheter allows the cardiologist to mapthe heart more quickly than traditional catheters by measuring multiplepoints of data at a time.

[0039] The preceding description has been presented with references topresently preferred embodiments of the invention. Persons skilled in theart and technology to which this invention pertains will appreciate thatalterations and changes in the described structures can be practicedwithout meaningfully departing from the principle, spirit and scope ofthis invention. Accordingly, the foregoing description should not beread as pertaining only to the precise structures described and shown inthe accompanying drawings, but rather should be read as consistent withand as support for the following claims, which are to have their fullestand fairest scope.

What is claimed is:
 1. A catheter comprising: an elongated catheter bodyhaving a proximal end, a distal end and at least one lumen extendinglongitudinally therethrough; a control handle attached to the proximalend of the catheter body; a mapping assembly mounted at a junction atthe distal end of the catheter body and comprising at least twoelongated flexible spines, each spine having a proximal end attached ator near the distal end of the catheter body and a free distal end,wherein each spine carries at least one electrode along its length; andat least two spine puller wires, each spine puller wire corresponding toone of the at least two spines, wherein each spine puller wire has aproximal end anchored in the handle and a distal end anchored at or nearthe distal end of its corresponding spine such that, in use,longitudinal movement of a spine puller wire relative to the catheterbody results in deflection of the spine to which the spine puller wireis anchored.
 2. The catheter of claim 1, wherein each spine comprises atip electrode mounted at the distal end of the spine.
 3. The catheter ofclaim 1, wherein each spine comprises an atraumatic tip mounted at thedistal end of the spine.
 4. The catheter of claim 1, wherein each spinecomprises a plastic cap mounted at the distal end of the spine.
 5. Thecatheter of claim 1, wherein each spine further comprises at least onelocation sensor.
 6. The catheter of claim 1, wherein the number ofspines ranges from two to twelve.
 7. The catheter of claim 1, whereinthe number of spines ranges from three to eight.
 8. The catheter ofclaim 1, wherein the catheter further comprises a catheter puller wirehaving a proximal end anchored in the control handle and a distal endanchored at or near the junction of the mapping assembly and thecatheter body such that, in use, longitudinal movement of the catheterpuller wire relative to the catheter body results in deflection of thecatheter body at or near the junction.
 9. The catheter of claim 1,wherein each electrode has a length up to about 2 mm.
 10. The catheterof claim 1, wherein each spine carries a plurality of electrodes, andthe distance between electrodes on each spine ranges from about 1 mm toabout 10 mm.
 11. The catheter of claim 10, wherein the distance betweenelectrodes on each spine ranges from about 2 mm to about 5 mm.
 12. Thecatheter of claim 1, wherein each spine carries from 2 to about 20electrodes.
 13. The catheter of claim 1, wherein each spine carries from3 to 10 electrodes.